Implantable defibrillator electrodes

ABSTRACT

Improved implantable defibrillator electrodes and methods of implanting such electrodes are disclosed. One embodiment of the defibrillator electrodes includes a flexible conductive mesh and non-conductive mesh. Another embodiment of the defibrillator electrodes includes a flexible conductive mesh, a non-conductive mesh and an insulator therebetween. A third embodiment of the defibrillator electrode compensates for the shape of a human heart. Methods for implanting the defibrillator electrodes include rolling an electrode and inserting the rolled electrode into a subxiphoid opening while thorascopically observing the insertion and manipulation of the defibrillator electrode.

FIELD OF THE INVENTION

This invention relates generally to electrical defibrillation, andrelates more specifically to particular types of implantabledefibrillator electrodes and methods of implanting them with a minimalamount of surgery.

DISCUSSION OF THE PRIOR ART

It is well known in the field of cardiology that certain types ofcardiac arrhythmias known as ventricular tachycardia and fibrillationcan be effectively treated by the application of electrical energy inthe form of pulses to the heart to defibrillate the fibrillatingtissues. Such defibrillation may be achieved by the application of suchpulses through electrodes applied to the chest of a patient or applieddirectly to a patient's heart tissue, if patient's chest is open duringsurgery.

More recent improvements have led to the development of implantabledefibrillators which automatically monitor the heart for arrhythmia andinitiate defibrillation when arrhythmia is sensed. Such devicestypically incorporate electrodes which are located either next to theheart or on an intravascular catheter, or both. Because the electrodesare closer to the heart tissue, than is the case with electrical paddlesapplied to the chest, implanted defibrillators require less energy todefibrillate than is required with external electrical paddles.Furthermore, energy supplied to electrodes applied to the chest usuallycause unwanted contractions of chest wall muscles.

However, major surgery such as median sternotomy or lateral thoracotomy,is generally necessary to implant defibrillator electrodes. Thesesurgical procedures can be very traumatic to a patient, and may haveadverse side effects such as surgical complications, or even worse,mortality. In particular, both median sternotomy and lateral thoracotomycause great patient discomfort during recovery. Furthermore the act ofretracting the sternum can cause painful rib fractures as well aspossible Brachial Plexus nerve impingement. Retracting the ribs, duringa lateral thoracotomy, can also cause painful rib fractures. Because ofthese risks, some patients who might otherwise benefit from animplantable defibrillator do not undergo surgery given the heretoforerisk to benefit ratio.

SUMMARY OF THE INVENTION

The method of the present invention provides access to the pericardiumand heart through small multiple opening sites (under 12 millimeterdiameter) made in the chest and xiphisternal area. In particular asubxiphoid opening, such as an incision or puncture, is used forinsertion of defibrillator electrodes, while an opening, such as anincision or puncture, between the 2nd rib and the 6th rib of a patientis used for observation via a thoracoscope. The exact location of theincision or opening is dependent upon a patient's particular anatomy. Atrocar is inserted into the latter opening to facilitate the insertionand withdrawal of the thoracoscope and/or instrumentation. Thedefibrillator electrodes may also be manipulated through this latteropening site. A third opening may be used for additional instrumentationand thoracoscopic observation as well as the later placement of a chestdrainage tube. Another method of the present invention first prepares adefibrillator electrode for insertion into a patient by rolling thedefibrillator electrode with a pair of handles and then using thehandles to insert the rolled defibrillator electrode into a patientthrough an opening in the patient.

One aspect of the apparatus of the present invention is directed towarda defibrillator electrode which includes a conductive wire mesh with asilicone backing, the silicone backing having a tail attached thereto.This allows the electrode to be pulled into place and then manipulatedwithin the pericardium. The base of the tail can also be used as anattachment point for single point fixation. After proper placement ofthe electrode, permanent fixation with titanium staples is performed. Inan alternative embodiment of a defibrillator electrode a siliconeinsulator is positioned between a conductive wire mesh and anonconductive mesh. A tail is attached to the nonconductive mesh.

The embodiments of the defibrillator electrodes of the present inventionallow placement of each electrode through very small openings andfurther allow fixation of the electrodes with metal staples withoutelectrical current exchange problems.

Another aspect of the apparatus of the present invention is directedtoward a carrier for use in transporting a rolled defibrillatorelectrode through an opening for implantation of the electrode within apatient.

Yet another aspect of the apparatus of the present invention is directedtoward an apparatus for rolling a defibrillator electrode andtransporting the rolled defibrillator electrode through a small openingwithin a patient.

These and other objects of the methods and apparatus of the inventionwill become more apparent when viewed in light of the following detaileddescription and accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a front perspective view of the upper chest region of a humanbody, with parts thereof shown in phantom, illustrating the preferredmethods of access for implanting defibrillator electrodes;

FIG. 2 is an exploded perspective view of a first preferred embodimentof a defibrillator electrode of the present invention;

FIG. 3 is an exploded perspective view of a second preferred embodimentof a defibrillator electrode of the present invention;

FIG. 4 is an assembled elevational sectional view taken along line 4--4of FIG. 3 illustrating the placement of a defibrillator electrodebetween the pericardium and the heart;

FIG. 5 is an exploded perspective view of a third embodiment of adefibrillator electrode of the present invention;

FIG. 6 is a transverse elevational view of the defibrillator electrodeof FIG. 5, illustrating the defibrillator electrode in a coiledposition;

FIG. 7 is an assembled elevational section taken along line 7--7 of FIG.5, illustrating the placement of the defibrillator electrode of FIG. 5between the pericardium and a heart;

FIG. 8 is a diagrammatic perspective view illustrating the positioningof trocars in accordance with one of the methods of the presentinvention;

FIG. 9 is a diagrammatic perspective view illustrating a method ofinserting a defibrillator electrode;

FIG. 10 is a diagrammatic perspective view illustrating a method ofpositioning a defibrillator electrode;

FIG. 11 is a diagrammatic perspective view illustrating a method ofpositioning a defibrillator electrode;

FIG. 12 is a diagrammatic perspective view illustrating a method offurther positioning a defibrillator electrode;

FIG. 13 is a diagrammatic perspective view illustrating one preferredplacement of a defibrillator electrode;

FIG. 13A is a diagrammatic perspective view illustrating the preferredplacement of a pair of defibrillator electrodes;

FIG. 14 is a diagrammatic perspective view illustrating the attachmentof a defibrillator electrode to the pericardium;

FIG. 15 is a diagrammatic perspective view illustrating an alternativemethod for the insertion and placement of a defibrillator electrode;

FIG. 15A is a side perspective view of a defibrillator electrodecarrier.

FIG. 15B is a top perspective view of the defibrillator electrodecarrier of FIG. 15A.

FIG. 15C is an end view of the defibrillator electrode carrier of FIG.15A.

FIG. 16 is a perspective view illustrating in part an alternative methodof rolling and retaining a defibrillator electrode for placement withina patient;

FIG. 17 is a perspective view illustrating in part the alternativemethod illustrated in FIG. 16 of rolling and retaining a defibrillatorelectrode for placement within a patient.

FIG. 18 is a diagrammatic perspective view further detailing the methodillustrated in FIGS. 16 and 17;

FIG. 19 is a diagrammatic perspective view illustrating in part thealternative method illustrated in FIGS. 16, 17 and 18 of rolling,relining, inserting and positioning a defibrillator electrode within apatient.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 illustrates the placement of trocars for both observation andinsertion of defibrillator electrodes between the pericardium and boththe front and rear surfaces of the heart. In particular, a first opening10, such as an incision or puncture is made in a patient 12 between thepatient's 2nd rib and 6th rib. The exact location of the first opening10 is dependent upon a patient's particular anatomy. Prior to theinsertion of a trocar 14, the patient's left lung is deflated to allowunobstructed observation through the trocar 14. The left lung isdeflated by drawing a vacuum through a tube which is inserted into theleft lung of the patient 12. This tube is routed to the left lung eitherthrough the mouth or nose of the patient 12. A thoracoscope 16 then isinserted into the trocar 14 to permit observation by a surgeon throughan eye piece 18 or through a video monitor which is connected to a videocamera. In such a case, the video camera is optically coupled to the eyepiece.

A second opening 20, such as an incision or puncture, which issubxiphoid, is then made and a second trocar 22 is inserted to pointupward toward a pericardium 24. A third opening may be made and used foradditional instrumentation or thoracoscopic observation as well as laterplacement of a chest drainage tube. As explained further herein, anendoscopic type grasping instrument 26 is utilized to insert a rolleddefibrillator electrode through the second trocar 22 or simply throughthe opening 20 (without a trocar) to thereby position the defibrillatorelectrode 28. Such a positioned defibrillator electrode 30 is shown inphantom. An endoscopic type cutting instrument 32 is utilized, asexplained further herein, to make an opening in the pericardium and tothereafter trim a tail 34 of the defibrillator electrode 28 after theelectrode 28 has been secured within the patient 12.

By entering on the left side of the patient 12, access is gained to boththe back side of the heart and the front side of the heart fordefibrillator electrode placement.

Referring now to FIG. 2, there is shown an exploded perspective view ofone embodiment of a defibrillator electrode 36 of the present invention.As will be appreciated by those skilled in the art, although theelectrode shown in FIG. 2 is basically circular, a differently shapedelectrode, for example an oval, may be utilized depending upon theprecise electrical conduction characteristics desired of the electrodeand of the physical shape and size of a particular patient's heart. Thedefibrillator electrode 36 consists of a platinum mesh 38 (onlypartially shown in FIG. 2) which attached to a silicone backing 40. Aswill be appreciated by those skilled in the art, although a platinummesh is utilized in the preferred embodiments of the invention, otherconductive materials which do not significantly interact with humantissue, may instead be utilized. The diameter of the platinum mesh 38 issubstantially less than that of the silicone backing 40. Thus, when theplatinum mesh 38 is substantially centered on the silicone backing 40,as detailed herein, a peripheral area 54 of the backing remains forattachment to the pericardium 24 by way of staples. In the preferredembodiment of the present invention, the silicone backing 40, whichfunctions in part as an electrical insulator, is attached to theplatinum mesh 38 with Silastic brand adhesive. Silastic brand adhesiveis a silicone based adhesive which is available from Dow CorningCorporation of Midland, Mich. The adhesive is applied only to thejunction of the periphery of the platinum mesh 38 and the siliconebacking 40.

A conductor 42 is conductively attached to the platinum mesh 38 and thisconductor 42 is encased within a silicone insulation 44. In thepreferred embodiment of the invention, the conductor 42 extends ontoplatinum mesh 38 for a length of approximately 8 mm to thereby provide asufficient electrical contact surface area between the lead wire 42 andthe platinum mesh 38. A periphery 45 surrounds the platinum mesh 38.Titanium staples 46, 48, 50 and 52, as detailed further herein, aredriven through the pericardium and into a peripheral area 54 of thesilicone backing 40, to thereby fixedly secure the defibrillatorelectrode 36 between the pericardium and the heart. In normal use theends of the titanium staples 46, 48, 50 and 52 are driven in a way tocause them to fold back toward the pericardium in the same manner aswith as shipping carton staples. An Ethicon EMS Endoscopic Multifeedstapler can be utilized to automatically drive and fold back suchstaples. By driving the staples 46, 48, 50 and 52 into the peripheralarea 54 of the silicone backing 40, away from platinum mesh 38,undesired changes in the conductive pattern of the platinum mesh 38 areprevented.

The defibrillator electrode 36 also includes a nylon tail 56, whichcorresponds to the tail 34 of FIG. 1. As detailed further herein, thetail 56 is attached to the peripheral area 54 and in use greatlyfacilitates the positioning and fixation of the defibrillator electrode36. In the preferred embodiment of the invention the tail 56 is amultifilament nylon cord. Once the defibrillator electrode 36 has beeninserted between the pericardium and the heart, the tail 56 can bepulled to further position the defibrillator electrode 36. Then, ifdesired, the tail 56 can be stapled to the pericardium to thereby allowa surgeon to pivot the defibrillator electrode 36 about the staple forfurther positioning.

Referring now to FIG. 3, a first alternative embodiment 57 of thedefibrillator electrode 36 of FIG. 2 is shown. In FIG. 3 a set ofnotches 58, 60, 62, 64, 66 and 68 are positioned about the periphery ofa silicone backing 69. Although FIG. 3 illustrates these notches to beV-shaped, it will be appreciated by those skilled in the art that theshape and number of such notches can be different. In addition, suchnotches may be placed unsymmetrically around the periphery of thesilicone backing 69. The notches 58, 60, 62, 64, 66 and 68 allow thesilicone backing 60 to more easily conform to a curved or sphericalsurface. Since the front and the rear of a human heart aresemi-spherical, the defibrillator electrode 57 shown in FIG. 3, whenplaced between the pericardium and the heart, can more easily conform tothe shape of the heart. As with the embodiment shown in FIG. 2, thediameter of the platinum mesh 38 is less than that of the siliconebacking 69, to thereby provide a peripheral area of the silicone backing69 into which staples may be driven.

Referring now to FIG. 4, the defibrillator electrode 57 is shown placedbetween a pericardium 70 and a heart 72. In the preferred embodiment ofthe invention, the silicone backing 69 is secured to the pericardium 70by a staple 74 and a staple 76 and other staples which are not shown.The staples 74 and 76 are each driven through the pericardium 70 andthrough the peripheral area of silicone backing 69. The staples 74 and76 are driven with an instrument (not shown) which causes the separateends of the staples to fold over against that side of the siliconebacking 69 which is adjacent to the heart 72. Such an arrangement notonly holds the defibrillator electrode 57 more securely, but alsominimizes the possibility of the staples touching the heart 72.Alternatively, the defibrillator electrode 57 may be secured to thepericardium 70 with sutures.

As illustrated in FIG. 4, the platinum mesh 38 of the defibrillatorelectrode 36 is generally in contact with the heart 72. The thickness ofthe silicone backing 69 is selected to accommodate the space between thepericardium 70 and the heart 72.

With reference now to FIG. 5, there is illustrated a second alternativeembodiment 78 of a defibrillator electrode. The defibrillator electrode78, as with both the defibrillator electrode 36 of FIG. 2 and thedefibrillator electrode 57 of FIG. 3, includes the platinum mesh 38, theelectrode wire 42 and the wire insulation 44. In contrast to thedefibrillator electrode 36 of FIG. 2, however, the defibrillatorelectrode 78 includes a thin polypropylene mesh 80, which in thepreferred embodiment of the invention is sewn onto a silicone spacer 82.The polypropylene mesh 80 also has attached to it the tail 56. Asexplained and illustrated further herein, after appropriate positioningbetween a heart and a pericardium, the defibrillator electrode 78 issecured with a set of staples 84, 86 and 88.

Referring now to FIG. 6, the defibrillator electrode 36 of FIG. 2 isillustrated in a rolled state. After placement between a heart and apericardium, the rolled defibrillator electrode with the assistance of apair of forceps 26, is unrolled as illustrated in phantom in FIG. 6.

FIG. 7 illustrates the placement of the defibrillator electrode 78 ofFIG. 5 between a heart 72 and a pericardium 70. As illustrated in FIG.7, the staples 84 and 88 are driven through the pericardium 70 and areembedded into the silicone spacer 82. As also illustrated in FIG. 7,because the staples 84, 86 and 88 do not extend all the way through thesilicone spacer 82, the defibrillator electrode 78 of FIG. 5 preventscontact between the staples 84, 86 and 88 and the heart 72 in the eventof trauma which forces the pericardium 70 toward the heart 72.

In further detail, as the staples 84 and 88 have a length somewhat lessthan the sum of the thickness of the pericardium 70, the thickness ofthe polypropylene mesh 80 and the thickness of the silicone spacer 82.In the embodiment shown in FIG. 7, the staples 84 and 88 extend abouthalf way through the silicone spacer 82.

Referring now to FIG. 8, a first method for intrapericardialdefibrillator electrode implantation is described in detail. The firstopening 10 is made between the 2nd rib and 6th rib of a patient 12, theprecise location dependent upon a particular patient's anatomy. Thefirst trocar 14 is then inserted into the first opening 10. The secondopening 20 is made subxiphoid and the second trocar 22 is insertedtherein. The subxiphoid opening 20 is used for instrumentation and theinsertion and manipulation of defibrillator electrodes.

Referring now to FIG. 10, the thoracoscope 16 is inserted into the firsttrocar 14 to permit observation through the eyepiece 18 or through avideo monitor which is connected to a video camera. In such a case thevideo camera is optically coupled to the eyepiece. The endoscopic typecutting instrument 32 is then inserted into the trocar 22 and is used todissect the pericardium 24. The endoscopic type cutting instrument 32 isthen removed from the trocar 22.

Referring now to FIG. 9, exterior to the patient 12 the endoscopic typegrasping instrument 26, under the direct manipulation by a surgeon,grasps the tail 56 of a rolled defibrillator electrode 78. Theendoscopic type grasping instrument 26 is then pushed through the secondtrocar 22 thereby pulling the tail of the rolled up defibrillatorelectrode 78 which in turn pulls the entire defibrillator electrode intothe patient 12. In the alternative, the tail 34 of the defibrillatorelectrode 78 can be held, together with the rest of the defibrillatorelectrode 78, and then pushed through the second trocar 22 into thepatient 12.

With reference to FIG. 11, once the defibrillator electrode 78 has beenpushed through the trocar 22 and into the pericardium 24, thedefibrillator electrode 78 is released by the endoscopic type graspinginstrument 26 to thereby allow the defibrillator electrode 78 to beginto unroll. To completely unroll the defibrillator electrode, it isgenerally necessary to utilize the endoscopic type grasping instrument26 to manipulate the defibrillator electrode 78.

The defibrillator electrode 78 is then pulled into its approximateposition, between the pericardium 24 and the heart. Under directthoracoscopic vision, the base of the tail of the defibrillatorelectrode is fixed to the pericardium 24 with an endoscopic typesurgical staple. The defibrillator electrode 78 is then manipulated bygrasping the proximal conductor of the defibrillator electrode with theendoscopic type grasping tool 26. After optimum placement of thedefibrillator electrode 78 has been determined by electrical testing,the defibrillator electrode is fixedly positioned by placing a secondsurgical staple through the pericardium 24 and through the peripheralarea of the defibrillator electrode 78. Additional staples may beutilized, as previously described, to further secure the defibrillatorelectrode. After final testing, the excess portion of the tail 56 isremoved from the defibrillator electrodes with the endoscopic typecutter 32. Alternatively, the defibrillator electrode 78 may be securedto the outside surface of the pericardium 24.

In order to connect the conductor 42 of the defibrillator electrode 78to a defibrillator electronics module (not shown), which is implantedwithin the abdomen of a patient, a tunnel is dissected between thepericardium and the diaphragm from the subxiphoid opening toward theposterior aspect of the pericardium. In further detail, silicone tubingis utilized to tunnel from the abdomen up to one end of the trocar 22adjacent to the subxiphoid opening 22. The silicone tubing is graspedwith a endoscopic grasping tool 26 and is pulled out of the patient 12up through the trocar 22. The silicone tubing is then secured to theconductor 42 and then pulled back through the trocar thereby routing theconductor down to the abdomen.

In some cases it may be desirable to attach the defibrillator electrodeson the outside of the pericardium instead of between the pericardium inthe heart. In such cases, the defibrillator electrodes illustrated inFIGS. 2 and 3 would be used. With such placement, however, the amount ofenergy required to defibrillate is generally larger.

FIG. 13 illustrates a final placement of the defibrillator electrode 78between a pericardium 24 and a heart.

With reference now to FIG. 13A, there is shown in phantom a seconddefibrillator electrode 79. The second defibrillator electrode 79 isimplanted in the same manner as described, except that this seconddefibrillator electrode 79 is attached to the pericardium 24 to bepositioned at to make contact with or near the rear side of the heart.

FIG. 14 illustrates the final placement of the defibrillator electrode78, after the openings 10 and 20 have healed.

Referring now to FIG. 15, an alternate method for defibrillatorelectrode implantation is described. As with the first described method,the left lung of the patient 12 is first deflated. The opening 10 ismade between the 2nd rib and the 6th rib of the patient 12. The exactlocation of the opening 10 is dependent upon a patient's particularanatomy. A trocar 14 is then inserted into the opening 10 and thethoracoscope 16 is inserted into the trocar 14 to permit observation.

A second opening 90 is then made between the ribs of the patient 12. Theexact location of the second opening 90 is dependent upon a patient'sparticular anatomy; however, the second opening 90 is below the firstopening 10. The defibrillator electrode 78 is rolled and placed into aflexible carrier 92. The flexible carrier 92 is then inserted throughthe second opening 90 using an endoscopic type grasping instrument (notshown). Once past the opening 90, the carrier 92 is pushed forward torelease it from the defibrillator electrode 78. Then the carrier 92 isretracted through the opening 90. The exposed portion of thedefibrillator electrode 78 is then grasped with an endoscopic typegrasping tool and inserted either extrapericardial or intrapericardialas previously described. Because of the shape and flexibility of thecarrier 92, the carrier 92 easily releases from the defibrillatorelectrode 78 when the defibrillator electrode 78 is pushed completelythrough the opening 90. Placement of the defibrillator electrode 78 andfixation thereof is performed as previously described with reference toFIGS. 8 through 13 except that such placement and fixation is performedwithout the benefit of a trocar.

Referring now to FIGS. 15A, 15B and 15C, there is shown in greaterdetail the flexible carrier 92. In the preferred embodiment of theinvention, the flexible carrier 92 consists of a partially enclosed area94 having a first wall 96, a second wall 98 and a floor 100therebetween.

The floor 100 extends the entire length of the flexible carrier 92 fromone end of the partially enclosed area to a tapered region 102. Thetapered region 102 is connected to an enclosed region 104.

A narrow end 106 of the carrier 92 is open as illustrated in FIG. 15C.In the preferred embodiment of the invention, the flexible carrier 92 ismolded from either silicon or other waterproof surgically compatiblematerial.

A second alternate method for defibrillator electrode placement isperformed as illustrated in FIGS. 16 through 19. Referring to FIG. 16, afirst handle 110 and a second handle 112, each having a slot or recess114 and 116 respectively at one end, are utilized to grasp adefibrillator electrode 118. As illustrated in FIGS. 16, opposite sidesof the defibrillator electrode 118 are inserted at into the slots 114and 116 of the first handle 110 and the second handle 112 respectively,so that conductor within the insulation 120 is relatively parallel toeach of the first and second handles 110 and 112.

Referring now to FIG. 17, the first and second handles 110 and 112 arethen turned toward each other to thereby roll the defibrillatorelectrode 118 into two connected rolled segments. The result is verycompact bundle that can be inserted into the patient 12 through a smalldiameter opening.

Referring now to FIG. 18, after the defibrillator electrode 118 has beenrolled, the handles 110 and 112 are used to insert the defibrillatorelectrode 118 through a subxiphoid opening 122. Once the defibrillatorelectrode is in approximately the desired position, as illustrated inFIG. 19 and as viewed through the eyepiece 18, the handles 110 and 112are rotated away from each other to thereby unroll the defibrillatorelectrode 118. The handles 110 and 112 are then pulled away from thedefibrillator electrode 118 out through the subxiphoid opening 122. Thedefibrillator electrode 118 may then be repositioned and secured asdescribed with respect to FIGS. 8 through 14.

FIGS. 1 through 19 of the drawing depict various preferred embodimentsof the present invention for purposes of illustration only. One skilledin the art will readily recognize from the specification, drawing andabstract that incisions and punctures are but two methods of creating anopening, and that alternative embodiments of the methods and structuresillustrated herein may be employed without departing from the principalsof the invention described herein.

We claim:
 1. An implantable defibrillator electrode, comprising:a flexible conductive mesh having at least one side; a flexible conductive wire conductively attached to the flexible conductive mesh; a flexible insulator affixed to one side of the flexible conductive mesh, the flexible insulator having a surface extending beyond a periphery of the flexible conductive mesh; and a tail attached to said surface extending beyond the periphery of the flexible conductive mesh.
 2. The implantable defibrillator electrode of claim 1, wherein the tail comprises:a flexible cord.
 3. The implantable defibrillator electrode of claim 1, wherein the attachment of the flexible conductive wire to the flexible conductive mesh is opposite to the attachment of the tail to the surface extending beyond the periphery of the flexible conductive mesh.
 4. The implantable defibrillator electrode of claim 1 wherein the flexible conductive mesh comprises:platinum wire.
 5. The implantable defibrillator electrode of claim 1 wherein the flexible insulator comprises:silicone.
 6. An implantable defibrillator electrode, comprising:a flexible conductive mesh having at least one side; a flexible conductive wire conductively attached to the flexible conductive mesh; a flexible insulator affixed to one side of the flexible conductive mesh, the flexible insulator having a surface extending beyond a periphery of the flexible conductive mesh; and a tail attached to the flexible insulator, wherein the tail comprises a flexible multifilament nylon cord.
 7. An implantable defibrillator electrode, comprising:a flexible conductive mesh having at least one side; a flexible conductive wire conductively attached to the flexible conductive mesh; a flexible insulator affixed to one side of the flexible conductive mesh, the flexible insulator having separate regions extending beyond a periphery of the flexible conductive mesh; and a tail attached to at least one of the separate regions.
 8. The implantable defibrillator electrode of claim 7, wherein the tail comprises:a flexible cord.
 9. An implantable defibrillator electrode, comprising:a round flexible conductive mesh; a flexible conductive wire conductively attached to the round flexible conductive mesh; and a flexible insulator having a periphery, the flexible insulator affixed to one side of the flexible conductive mesh, the flexible insulator having a surface extending beyond a periphery of the flexible conductive mesh, the flexible insulator further having at least one notch at its periphery.
 10. The implantable defibrillator electrode of claim 9 wherein said notch is wedge shaped.
 11. An implantable defibrillator electrode, comprising:a flexible conductive mesh; a flexible conductive wire conductively attached to the flexible conductive mesh; a flexible nonconductive mesh; and a flexible insulator, wherein the flexible insulator is secured to a surface of each of the flexible conductive mesh and the flexible nonconductive mesh and the flexible insulator is between the flexible conductive mesh and the flexible nonconductive mesh.
 12. The implantable defibrillator electrode of claim 11 further comprising:a tail attached to the flexible nonconductive mesh.
 13. An implantable defibrillator electrode, comprising:a flexible conductive mesh; a flexible conductive wire conductively attached to the flexible conductive mesh; a flexible nonconductive mesh; and a flexible insulator, the flexible insulator secured to the flexible conductive mesh and the flexible nonconductive mesh, wherein the flexible insulator is between the flexible conductive mesh and the flexible nonconductive mesh and wherein the flexible nonconductive mesh includes a surface extending beyond a periphery of the flexible insulator.
 14. An implantable defibrillator electrode, comprising:a flexible conductive mesh having at least one side; a flexible conductive wire conductively attached to the flexible conductive mesh; a flexible insulator affixed to one side of the flexible conductive mesh, the flexible insulator having a surface extending beyond a periphery of the flexible conductive mesh; and a tail attached to the flexible insulator, wherein the tail comprises a non-conductive flexible cord. 